A shielded electrical connector is provided having several rows of contacts inside the housing and an outer metallic shell for the purpose of shielding. Such shielded electrical connectors are widely used in computers, work stations and other types of electronic office equipment for the connection of signal-carrying lines.
In such shielded electrical connectors, the metal shell prevents electromagnetic noise from penetrating into the connector, but it does not eliminate the problem related to cross-talk between contact pins. In order to solve the problem of cross-talk, a metal sheet is installed between the rows of the contact pins.
FIG. 10 is an oblique view of an electrical connector of a conventional type as disclosed in Japanese Utility Model 49-6543. As can be seen from FIG. 11, pin-shaped contacts 2 are arranged basically in two rows separated by a metal sheet 2. At the time of connection, this metal sheet 2 is inserted in slits 3 of the housing shown in FIG. 10. FIGS. 12 and 13 are oblique projections of the connector parts shown in FIGS. 10 and 11 with cross-sections made along lines A--A' and B--B'. The metal sheet 2 has a tie-in 4 which, at the time of connection, comes in contact with tie-in 6, thus electrically separating the two rows of contacts 1.
However, the trend of decreasing dimensions of electronic equipment developed in recent years led to a necessity to reduce the dimensions of the connectors for interface devices. For example, in high-performance CPU's operating at 32 bits used in electronic equipment, the number of contacts in a given interface connector may be as high as 200. As a result of the requirements to increase the number of contacts in such small connectors, distances between the contacts were drastically reduced, which led to increased problems of cross-talk and insufficient speed of operation. In such cases, if measures were taken in the form of a metal sheet 2, such as is shown in FIGS. 10-13, this sheet often failed to produce a proper connection at the time of joining the two halves of the connector which often resulted in damage.
Another effect of size scale-down is that the layer of insulating material between the contacts becomes very thin, which may lead to damage of the housing. In addition, if tie-ins 4 and 6 are provided for the metal sheet 2, as shown in FIGS. 10 and 13, the pitch of the signal contact pins 1 must be increased, which defeats the requirement of the decrease in dimensions of the connector.
Considering the above circumstances, the purpose of the instant invention is to offer a mechanically strong, miniature shielded electrical connector having a high density of contacts with substantially reduced cross-talk and reduced noise interference between the rows of contacts.